In case of highly monolith NPs, this [[tau].sub.b] tends toward bulk lifetime
of substance, while in more loose aggregates of many NPs, it is higher reflecting their reduced compactness.
The open circuit voltage increased about 16 mV at lower temperature, this is because the low temperature (800[degrees]C) passivation has higher bulk lifetime
than the high temperature (1050[degrees]C) passivation.
Rey-Stolle, Impact of metal-organic vapor phase epitaxy environment on silicon bulk lifetime
for III-V-on-Si multijunction solar cells, Solar Energy Materials and Solar Cells, Volume 124, 2014, Pages 17-23, ISSN 0927-0248, http://dx.doi.org/10.1016/j.solmat.2014.01.034.
where W is the thickness of the wafer and [[tau].sub.bulk] represents the bulk lifetime
of the wafer, which is a combined result of Auger, radiative, and Shockley-Read-Hall recombination.
The effective lifetime ([[tau].sub.eff]) is a combination of bulk lifetime
([[tau].sub.bulk]) and surface lifetime ([[tau].sub.sur]) as follows: